That's only half true. While it's true that the in-game server browser would cease to function, you could absolutely still connect and play with people on indep

That's only half true. While it's true that the in-game server browser would cease to function, you could absolutely still connect and play with people on independent servers. And this isn't a hypothetical; there were (probably still are) many independent server trackers and aggregators allowing you to find servers without Valve's servers being up. And I know that this all works because I'd host offline LAN parties with friends were we'd run all sorts of offline-compatible games like TF2, CS, Quake, Unreal, Halo, Sourceforts, Gmod, etc.